An electric coil (or simply a “coil”) is formed by winding a conductor (usually an insulated solid copper wire) around a non-conductive core to create an inductor. One loop of wire is referred to as a turn, and a coil consists of one or more turns. In electronic circuits, electrical connection terminals referred to as taps are connected to a coil. A completed coil assembly with taps is often called a winding. Coils are used in different applications, such as in power transformers and electromagnets. Coils are also used in inductive charging and resonant inductive coupling applications, where energy is transferred between two objects through inductive coupling, e.g., without a conducting medium between the two objects. In inductive charging, there is a relatively small gap between two coils, which are located on the sender and receiver sides of the energy, e.g., within two respective devices. Inductive charging is considered a short-distance “wireless” energy transfer, since charging is achieved without using wires between the two devices. For example, inductive charging applications include wireless battery charging devices. Resonant inductive coupling is the near field wireless transmission of electrical energy between two coils that are tuned to resonate at the same frequency. Resonant inductive coupling applications can achieve longer energy transfer distances than inductive charging applications. For example, resonant inductive coupling applications include near-field wireless communications, such as radio-frequency identification (RFID) devices.